Quote:
Originally Posted by Kellyjones
Ok so what about that stamp on the side of the Montana just under my Lippert level up system that "Tire and Loading Information"? It tells you the tire size and cold pressure which says "ST235/80R16E" and 80 PSI! Does that mean that 80 PSI should be all I run on the Montana? Still have not located that PSI stamp on the dang wheel! It also says the weight of the cargo should never exceed 3330 lbs. This is so confusing. I normally just pull up the the tire dealer in my SUV and ask for tires and they put them on. This is ridiculous.
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You have to divorce yourself from anything you've previously known about tires. Nothing about P-metric or even Light Truck E-rated tires for SUVs applies here.
The example ST E-rated tire from the placard carries a max psi rating of only 80, as are all E-rated tires. Put more than 80psi in and you'll blow them up or exceed the wheel rating, and yes, wheels can crack. What does that mean with respect to the placard, provided by RV mfgr.? All it means is the RV mfgr. reviewed the tire mfgrs. specs for that tire and has determined it can carry the load it has computed on the axles, plus your stuff at 3,330lbs. They can say they did their due diligence, and any failure is then on the tire mfgr.
The problem with ST tires, until very recently, has been cheap Chinese knockoffs that are not tested to US standards since they're not intended for passenger use. The result has been a significant number of failures with damage to RVs, busted vacations and increased driver stress.
Let's take a 14,000 FW as an example. With an avg. 20% on the pin, you're left with 11,200 on the axles (14,000-2,800). Dividing that 11,200 by 4, each tire can carry 2,800lbs. We're still within avg. E-rated tire specs (3,500-3,700lbs), but let's throw in the 3,330lbs of your stuff, 833lbs each, so each tire is now carrying 3,633lbs. Oops.
Until very recently, KS and other FW mfgrs. have installed the most minimally rated tire, which I'm sure is related to their bottom line.
Coupled with a poor tire, it's a recipe for disaster.
So, what to do? If you have a heavy FW, it certainly can't hurt to upgrade to a good, ST G-rated tire, and 110psi wheels. It may be, at your weight, you don't have to use max psi (using the tire mfgr. load table). The Sailun has proven, at least anecdotally, to be a winner. The GY Endurance is getting good reviews, too. There are a handful of other ST tires being talked about positively (Hercules, Cooper, etc.), but their track record is not proven, IMHO. Hope this helps.